1. Field of the Invention
This invention generally relates to a bicycle chain tensioner. More specifically, the present invention relates to a bicycle chain tensioner for a bicycle.
2. Background Information
A bicycle typically uses a chain drive transmission for transmitting a pedaling force to a rear wheel. The chain drive transmission of a bicycle often uses derailleurs to selectively move a chain from one of a plurality of sprockets to another for changing speeds of the bicycle. The sprockets provide different gear ratios based on different diameters of the sprockets. As the chain is moved from one of the sprockets to another, the chain will be naturally loosen, which could allow the chain to disengage from the sprocket, or tighten, which could cause the chain to break, due to the different diameters of the sprockets. Thus, a bicycle chain tensioner is conventionally used for properly applying tension to the chain in a chain drive transmission. A conventionally known bicycle chain tensioner is pivotally mounted to the bicycle with a movable arm supporting a tension sprocket at its free end. The bicycle chain tensioner also includes a coil spring that biases the tension sprocket into engagement with the chain.
Referring to U.S. Pat. No. 7,955,205, a conventional chain tension applying device is disclosed. With this chain tension applying device, a securing position adjust mechanism adjusts a securing position of a tension member to a bracket in a first direction by sliding. The first direction is substantially parallel to an axial direction of a rotation shaft of a rear sprocket. Furthermore, referring to International Publication No. WO93/01967, a derailleur for multi-speed bicycle is disclosed. With this derailleur for multi-speed bicycle, a chain take-up device includes an elongated member extending along a bar, movable longitudinally along and guided by the bar and carrying at its rear end a drive chain tensioning member. The chain take-up device pivotally moves following a pivotal motion of the bar which is provided by a cooperation of a pivot pin, a lever, a hook and a slot. The pivotal motion of the bar provides a gear shifting of a bicycle. Moreover, referring to U.S. Pat. No. 7,905,805, a tension device of a bicycle derailleur is disclosed. With this tension device, a second pulley for applying tension to a drive chain is rotatably mounted on a second cage, and the second cage is slidably engaged to a track of a slide device such that the cage can linearly slide along the track. The tension device is mounted by first and second bushing members that absorbs and dampens impacts on any component attached to a mounting frame, which also allows a pendulum motion of the tension device.